/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.gds.procedures.algorithms.community;

import org.neo4j.gds.api.Graph;
import org.neo4j.gds.api.GraphStore;
import org.neo4j.gds.api.IdMap;
import org.neo4j.gds.applications.algorithms.machinery.StreamResultBuilder;
import org.neo4j.gds.beta.pregel.PregelResult;

import java.util.Map;
import java.util.Optional;
import java.util.stream.LongStream;
import java.util.stream.Stream;

import static org.neo4j.gds.sllpa.SpeakerListenerLPA.LABELS_PROPERTY;

class SpeakerListenerLPAResultBuilderForStreamMode implements StreamResultBuilder<PregelResult, SpeakerListenerLPAStreamResult> {

    @Override
    public Stream<SpeakerListenerLPAStreamResult> build(
        Graph graph,
        GraphStore graphStore,
        Optional<PregelResult> result
    ) {

        if (result.isEmpty()) return Stream.empty();
        var labels = result.get().nodeValues().longArrayProperties(LABELS_PROPERTY);

        return LongStream.range(IdMap.START_NODE_ID, graph.nodeCount())
            .mapToObj(nodeId -> {
                // for every schema element
                var values = labels.get(nodeId);
                return new SpeakerListenerLPAStreamResult(graph.toOriginalNodeId(nodeId), Map.of(LABELS_PROPERTY, values));
            });
    }

}
